1. Field of the Invention
The subject disclosure relates to systems for automatic fire suppression, and more particularly to an improved system for automatically delivering compressed air foam (CAF) to a hazard area that is typically difficult to safely and properly access. The systems are also effective for delivering foam and like substances to cover and control biohazards.
2. Background of the Related Art
For centuries, man has battled unwanted fires. As technology has developed, the fire fighting techniques have matured from the bucket brigade to highly specialized vehicles, systems and chemicals. However, in many instances such as off-shore drilling platforms, boats, bulldozers and the like, access to water distribution networks or access by firefighting vehicles is not available along with other technical challenges. When a fire is relatively small, use of portable fire extinguishers is common. Further, depending upon the source of the fire, water may not be an appropriate agent for suppression. As such, emergency vehicles and portable extinguishers often deliver foam, non-water solutions, water with chemical additives for additional suppression capability and the like.
Use of portable extinguishers from hand-held versions and larger cart-like versions have been widely used and well understood in the art. For example, U.S. Pat. Nos. 5,881,817 and 6,089,324 to Mahrt, each of which is incorporated herein by reference, disclose a portable fire suppression system using cold compressed air foam. The portable system includes a manifold with a mixing chamber for expanding and accelerating the foam through the manifold by injecting cold compressed air adjacent the manifold inlet and at a 68 degree angle relative to the flow direction.
Technology continues to evolve in the area of fire suppression. An exemplary technique is illustrated in U.S. Pat. No. 6,328,225 to Crampton (the Crampton patent), which is incorporated herein by reference. The Crampton patent discloses a rotary nozzle for a CAF fire extinguishing system. In a preferred embodiment, two orifices of unequal size are provided on opposite sides of the lower part of a tubular barrel with closed ends. As a result of the asymmetrical disposition of the two orifices with respect to the axis of rotation of the barrel, jets are directed downwards, tangentially to the axis of rotation of the barrel, causing the barrel to rotate about its axis.
Another exemplary device is disclosed in U.S. Pat. No. 6,082,463 to Ponte (the Ponte patent), which is incorporated herein by reference. The Ponte patent discloses a concealed or covered sprinkler for a conventional (e.g., water-supplied) fire prevention system. When the ambient temperature exceeds the melting point of a solder joint, leaf springs force the sprinkler cover open and, moreover, when the ambient temperature exceeds the release temperature of a thermally responsive structure, a lever structure forces a cap from an orifice through which pressurized water is forced.
U.S. Pat. No. 5,441,113 to Pierce, incorporated herein by reference, discloses an automatic foam fire extinguishing system comprising a source of pressurized foam, a distribution system for distributing air and the foam, and a plurality of sprinkler heads that dispense the air and foam.
U.S. Pat. No. 3,441,086 to Barnes, incorporated herein by reference, discloses a water-powered fire-fighting foam generator and a dispensing nozzle. In a preferred embodiment, pressurized foam solution travels through a passageway into a pair of reaction nozzles that spray the foam solution onto the inner surface of a perforated, cylindrical wall. The force of the solution causes the reaction nozzles and, consequently, the axial flow fan to rotate. As the axial flow fan rotates, it forces air down and then radially outward through the perforations in the cylindrical wall.
Further, advances in technology are often gained by study and use of hazardous or infectious materials such as carcinogens and active virus cultures. As a result of handling such highly toxic and/or dangerous substances, suppression systems are needed to cover and/or control such substances. Although effective suppressants have been developed, an improved system for delivering these suppressants is needed.